Chocolate Mousse Cake

Even though a typical chocolate mousse cake is usually made with one thick layer of mousse atop a very thin layer of cake, we're firm believers that a rich mousse is best balanced with something more substantial than a negligible amount of cake.

Don't misunderstand us—we're not afraid of chocolatey richness (this cake is made of three distinct layers of chocolate), but we think a layer of velvety chocolate cake should be almost as thick as the layer of mousse on top of it. This balances the silky mousse with something fluffy and tender.

On top of this marriage of chocolate cake with chocolate mousse, we spread a thin layer of dark chocolate ganache, for decadence in taste and appearance.

Learn how to make chocolate mousse cake. We recommend serving this dessert with fresh berries. Their simple sweetness and acidity allows you to enjoy more of the dessert than you could on its own.

What Is Chocolate Mousse?

Rich, velvety chocolate mousse is made by combining melted chocolate with whipped eggs and cream, for a light and airy, but decadently chocolaty dessert.

The word mousse in French translates to foam or froth, accurately describing the texture of this whipped dessert. Most likely an evolution from savory mousses made with fish or meat, the first recipe for chocolate mousse came about in the 18th century, with the dessert gaining popularity in the 19th and 20th centuries.

Over time, chocolate mousse has become a staple dessert around the world. While it may be served in the finest restaurants, you'll find it can easily be made at home with a few simple steps.

Ingredients for Chocolate Mousse Cake

A fudgy chocolate cake, made with coffee and dark brown sugar to enhance its deep flavor, provides a tender base for a velvety chocolate mousse featuring 60 percent bittersweet chocolate. To make chocolate mousse cake, you'll need:

For the cake:

• All-purpose flour: Gives the cake its structure. A lower protein flour won't work here, so don't substitute.
• Baking soda: A leavening agent to help the cake rise.
• Kosher salt: Balances and enhances the overall flavors of the cake.
• Unsweetened cocoa powder: Adds a deep, chocolaty flavor.
• Dark brown sugar: Sweetens and adds moisture to the cake. You can use light brown sugar if necessary.
• Strong hot coffee: Enhances the chocolate flavor and acts as a liquid base for the cake batter.
• Vegetable oil: Adds richness and tenderness. Canola oil will also work.
• Apple cider vinegar: Reacts with the baking soda to help the cake rise, and brightens the rich flavors.

For the mousse:

• Heavy cream: Whipped to add a creamy richness and airy quality to the mousse.
• Large egg yolks: Adds richness and structure to the mousse.
• Granulated sugar: Sweetens the mousse.
• 60% bittersweet chocolate chips: Melted and added in for a chocolatey richness and to help the mousse set properly when chilled.
• Powdered sugar: Sweetens and helps stabilize the mousse.

For the ganache:

• 60% bittersweet chocolate chips: For a decadent, chocolatey glaze. You can use a different type if you like, but the darker chocolate really elevates the whole cake.
• Heavy cream: Thins the chocolate for a spreadable topping.

Fresh berries and whipped cream, to garnish the dessert.

How To Make Chocolate Mousse Cake

Making a chocolate mousse cake from scratch might seem like a tall order, but in reality, it's no different than making a classic chocolate cake, with a lightened chocolate pudding to go with it. Full instructions are below, but here's a brief recap before you get started:

• Step 1. Make the Cake: Prepare the oven and springform pan. Whisk to combine the dry ingredients. In another bowl, whisk together wet ingredient, and then combine the two until smooth. Pour into prepared pan and bake until a wooden pick inserted comes out clean. Set aside to cool.
• Step 2. Make the Mousse: Heat cream in a saucepan until just beginning to steam. Slowly stream half of the hot cream into a bowl with a mixture of egg yolks and sugar. Return this mixture to saucepan, and heat until just beginning to boil. Remove from heat and whisk in melted chocolate. Cool to room temperature. Whip remaining cream with powdered sugar. In 3 additions, fold the cream into the chocolate mixture. Pour over cake layer and spread evenly. Chill 5 hours or overnight until set.
• Step 3. Make Ganache: Add chocolate to a saucepan with the heated cream. Let sit for 2 minutes, then whisk to combine. Cool to room temperature.
• Step 4. Assemble the Cake: Run a hot wet towel around the springform pan to release cake. Remove cake pan and transfer cake to a platter. Top evenly with ganache and garnish with fresh berries and whipped cream if desired.

Tips for the Best Chocolate Mousse Cake

For the best chocolate mousse cake, keep these simple tips in mind:

• Don't overmix or overbake: For the most tender, moist chocolate cake layer, avoid overmixing, which could cause the cake to become more dense and rubbery in texture. Bake only until a wooden pick inserted comes out clean, even with a few moist bits, to avoid a dry result.
• Fold gently: Mousse should be light and airy, so keeping as much lift in the mixture as possible is the key to the best texture. When adding the whipped cream to the custard, fold gently and avoid overmixing.
• Chill until set: It might be hard to wait for such a decadent dessert to be ready, but chill as directed to avoid a messy result.
• Coat evenly: If you prefer, leave the cake in the pan and coat with ganache before unmolding for an even coating that won't run down the sides of the cake.

What Type of Chocolate Is Best for Chocolate Mousse?

Just as recommended when cooking with wine, you'll want to choose a chocolate for baking that's high-quality and delicious enough to stand on its own. For this cake recipe, we call for 60 percent bittersweet chocolate chips. Note that you can swap the chips with chopped 60 percent chocolate bars if desired. Chocolate bars often have a higher cocoa butter content and fewer stabilizers, meaning they'll melt even more easily into your mousse mixture. You'll need about six ounces of chocolate for each cup called for.

If you're a fan of darker chocolate varieties, you can increase the percentage to a 70 percent or higher dark chocolate. Note that the darker the chocolate, the more bitter the flavor.

Chocolate Mousse Cake Variations

To change up this chocolate mousse cake, consider these variations:

• Change up the cake layer: The cake base for this mousse cake can be anything you prefer. While a fudgy chocolate cake is classic, you can also opt for red velvet, confetti, or any other cake you love.
• Soak the cake: For additional flavor, soak the cake with a flavorful syrup (even a boozy one) before topping with mousse.
• Flavor the mousse: Fold in a splash of vanilla or peppermint extract, a sprinkle of instant espresso powder, hint of orange zest, or a dash of spice for extra flavor.
• Swap the chocolate: Swap the 60 percent chocolate with white, milk, or an even higher percentage of dark chocolate for a unique twist.
• Thin the ganache: For a show-stopping chocolate ganache drip, add an additional splash of cream or oil to the ganache, and warm until smooth. Pour over the unmolded cake and spread evenly, allowing it to drip slowly down the sides.
• Toppings: Drizzle the cake with caramel sauce when serving, top with chocolate curls, chopped candy bars, toasted coconut, or sprinkles for a festive touch.

Can I Make Chocolate Mousse Cake Ahead?

This cake can be made and refrigerated up to two days before serving, or components can be prepared further in advance, if needed.

To make this cake ahead, prepare as directed. Leave the cake in the springform pan when topping with ganache so you can wrap it easily without marring the ganache topping. Unmold before serving.

You can also make the cake layer further in advance. Bake the cake and cool to room temperature, then wrap and freeze, whether unmolded from the cake pan or left inside, for up to one month for the freshest flavor. Thaw at room temperature, and return to the cake pan if needed. Top with mousse and ganache as directed the day of or day before serving.

How To Store Leftover Chocolate Mousse Cake

Refrigerate leftover slices of chocolate mousse cake for up to four days or freeze for up to two months well-wrapped or in an airtight container. If frozen, thaw in the refrigerator for an hour or two before serving.

More Decadent Chocolate Cake Recipes You'll Love

If rich chocolate cakes are just what you're craving, these recipes are sure to give you lots of inspiration to get baking:

• Chocolate-Praline Cake
• One-Bowl Chocolate Cake
• Bourbon-Chocolate Cake with Browned Buttercream Frosting
• Chocolate Fudge Layer Cake with Caramel Buttercream
• Coca Cola Chocolate Cake
• Little Layer Chocolate Cake
• Triple-Layer Chocolate-Caramel Cake
• Rudolph's Chocolate Truffle Cake
• Chocolate Mayonnaise Cake

Editorial contributions by Katie Rosenhouse.